I own a 3' gauge 1922 Plymouth DL (delivered in January 1923) built for Old Mission Cement in San Juan Bautista CA... It was built with roller bearings, as were most if not all Plymouth locomotives. Leslie Salt at Saltus CA... (Amboy) used rollers on their 4 wheel dump cars... This is not new or unknown technology...
Randy Hees
Director, Nevada State Railroad Museum, Boulder City, retired
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